Segmented winding mandrel



Feb. 16, 1965 A. 6. SMITH ETAL 3,159,718

SEGMENTED WINDING MANDREL Filed April 25, 1963 3 Sheets-Sheet 1 AARON G. sMlTH ORENZO 2 Mocks 1N VEN TORs FIG. 5 ywxfizw ATTORNEY Feb. 16, 1965 A. G. SMITH ETAL SEGMENTED WINDING MANDREL 3 Sheets-Sheet 2 Filed April 25, 1963 FIG.3

AARON 6-. SMITH AORENZOZ MooRE INVENTORS ATTORNEY United States Patent 3,169,713 SEGMENTED WENDWG MANDREL Aaron G. Smith and Lorenzo D. Moore, Nashviile, Tenn, assignors to Ferro Corporation, (Iieveland, Ghio Subsn'tuted for abandoned application Ser. No. 179,533,

Mar. 12., E62. This application Apr. 25, 1963, Sci.

4 Claims. (*(Zl. 242-4s.s

This invention deals generally with the manufacture of continuous strand material, and more particularly to a high speed winding mandrel for the attenuation of glass fibers from appropriate orifices in a platinum bushing, crucible, or other suitable source of molten glass.

The modern technology of fiberglass production demands extremely high speed winding mandrels for the attenuation of glass fibers, capable of revolutions per minute in exces of the equivalent of ten thousand peripheral feet per minute.

It can be readily understood therefore that the ideal mandrel for such purpose should possess certain physical characteristics such as high strength, perfect dynamic balance, a design expeditions to rapid disassembly and repair, as well as a smooth, unbroken working surface.

The customary design of most mandrels heretofore has been such that a somewhat flexible tube, capable of slight distention from internal stresses, is slipped around the peripheral working surface of the mandrel and it is this hollow tube, usually of cardor fiberboard, upon which the glass fiber material is wound at high speeds.

In order to minimize slippage of the hollow winding tube over the working surface of the mandrel, said working surface is usually characterized by some means, incorporated within the mandrel, whereby, under the speed of rotation, centrifugal force exerts a pressure against the interior of the winding tube. In addition to reducing slippage of the tube on the mandrel, the pressure exerted against the interior of the winding tube during rotation also tends to counteract the high compressive forces built up as more and more fibrous material accumulates on the winding tube. Such means are normally spring and/or centrifugally activated. After the required amount of strand has been accumulated on the winding tube, and the mandrel brought to rest, interior centrifugal pressure against the tube is of course released permitting the tube to be readily slipped off the mandrel.

Exemplary of the various means devised to hold the winding tube snugly to the mandrel, as well as exert centrifugally induced pressure against the interior of the winding tube during rotation are the devices disclosed in United States Patents 2,891,798 to Smith, 2,457,786 to v Furthermore, since most glass fiber attenuating opera-' tions involve a size or binder applied to the strand just prior to its being wound on the winding tube, such size or binder compositions still being somewhat sticky or tacky at the instant the fibrous material is spun onto the winding tube, the multiplicity of protruding ridges or fingers resulting from the numerous raised sections distributed around mandrels used heretofore caused an unfavorable accumulation of said size or binder material in the vicinity of said sections, due to ridge-like distortion of the tube corresponding to said sections, this of course tended to defeat the purpose of the size or binder composition since some areas of the wound fibers were thus deprived of the required amount of size or binder composition, while other areas acquired an excessive concentration thereof thus reducing the utility and uniformity of the fibers when later incorporated into a laminate as a plastic reinforcing agent.

Accordingly, we feel that our novel invention has resulted in a mandrel which is much lighter than heretofore known, is relatively simple for ease of disassembly and repair, and presents a substantially continuous and uninterrupted working surface to the interior of a distensible winding tube so as to eliminate spot concentrations of size or binder resulting from distortion thereof, yet at the same time provide suificient and evenly distributed pressure against the interior of said winding tube to eliminate slippage of the tube, and counteract cornpressive forces of the fibrous material being wound thereon.

It is therefore an object of this invention to provide a winding mandrel for strands and fibers.

It is also an object of this invention to provide a rotatable mandrel for winding strands and fibers, said mandrel having a working surface composed of a multiplicity of cylindrical segments.

It is a further object of this invention to provide a means for rotating a distensible hollow tube at high rates of speed, in excess of the equivalent of ten thousand peripheral feet per minute, for the purpose of winding thereon fiber or strand material.

it is also an object of this invention to provide a more truly cylindrical package of strand or fiber material in which such package has sufiered" minimum distortion during the winding operation.

It is yet another object of this invention to produce a wound package of fiber or strand material which has had applied thereto, immediately prior to Winding on a mandrel, a size or hinder material, said strand or fibers in said package having evenly distributed throughout their length said size or hinder material and having a minimum of binder or size composition concentration at any given point along their length due to ridges or like protrusions in the working face of the winding mandrel.

It is a further object of this invention to provide a method for winding fiber or strand material directly onto a winding mandrel working surface, without the need to interpose between said surface, and said fiber or strand material, an intermediate winding tube.

The foregoing and related objects will become apparent from the specification which follows and the attached drawings wherein:

FIG. 1 is a schematic diagram of the principal steps involved in attenuating filaments from a molten source and collecting them on a mandrel in the form of a package.

FIG. 2 is a highly simplified exploded view of our novel winding mandrel.

FIG. 3 is a detailed front elevation view of mandrel.

FIG. 4 is a section of said mandrel through the plane 4-4 of FIG. 3.

FIG. 5 is a perspective view of one end of one of the segments of our novel winding mandrel.

FIG. 6 is an enlarged view of spring plunger means 14 said ' shown in FIG. 4, as will be hereinafter discussed in more detail.

Briefly and simply stated the winding mandrel of our invention consists of a substantially smooth cylinder as the working face thereof, capable of being rotated at speeds up to, and in excess of, the equivalent of ten thousand peripheral feet per minute, said smooth cylindrical working surface consisting of two or more indifunction of our invention, refer to FIG. 1 wherein is shown a platinum bushing 4 containing molten glass, a multiplicity of glass filaments 5, being drawn from suitably situated orifices in the bottom of said bushing, gathering means 6 wherein the filaments are continuously converged into strand 8, size or binder applicator means 7, traversing means 9 for continuously traversing the strand back and forth across the face of the rotating mandrel generally indicated at 1, which activates the entire operation as can be readily seen, said mandrel rotating at high speed in the direction shown, thus continually drawing the filaments 5 from the bushing 4- past gathering point 6, size or hinder applicator 7, and traversing mechanism 9, which is also rotated at a high speed by means not shown, mandrel 1 being rotated by any suitable means suc as an electric motor, not shown. I

Referring now to FIG. 2, there is depicted a highly circular members 2 and 2' respectively with plunger 18 in its compressed position. As will be seen, when compressive stress is removed from circular segments 3a., 3b, and 3c, plunger means 1.4 will urge said segments radially outwardly from hub 10 of mandrel 1 by the distance indicated by b, or untilannular flange 22 of any given segment 3a, 322, or 30 contacts, and is restrained from further radially outwardly movement by,

the corresponding annular flange 23 of circular members 2 and 2' respectively. Thus, cylindrical segments 3a, 3b, and 3c are maintained in Variable radialspaced relationship with respect to hub all, the outer limit being a function of the movement permitted by engaging flanges 22 and 23, the compressive limit occurring when a cylindrical segment contacts an edge of a circular member 2 and/or 2'. I a

As is readily apparent from FIGS. 4 and 5, segments 3a, 311, etc., display a progressively lesser dimension, in

"cross-section, toward the extremities thereof, than in the simplified representation of our winding mandrel which.

shows only the essential components in exploded juxta- 5 position in order to more easily illustrate the principles involved.

Basically, FIG. 2 shows that our mandrel consists in .a rotatable hub ltl having fixed on each end thereof circular members 2 and 2 with cylindrical segments 3a, 3b, and 3c whose convex areas form the working (surface of said mandrel, said segments adapted to engage circular members 2 and 2, enveloping hub 1% to thereby form a relatively smooth cylinder as a wind ing mandrel having no protrusions, flanges or ridges breaking the working surface thereof, the only interruption in said surface being the substantially snug joint at the juncture of said segments. As illustrated, our preferred embodiment includes three cylindrical segments subtending respectively, angles of 120. However, two to eighteen segments may be used, subtending 180 and 20 respectively, without departing from the principle of our invention.

Referring now to FIG. 3, a front elevation view of the mandrel is shown in more detail, wherein the joints between segments 3a, 3b, and 3c are shown wider than necessary for ease of illustration.

FIG. 4 is a cross section taken along the line 4-4 in FIG. 3 and the details of the mechanical operation of our mandrel are best illustrated by this section. Flanged rear circular member 2 and front circular member 2 are fastened to hub Ill by suitable screw means 12 and 13 respectively. I

Spring activated plunger means 14 are secured as shown in FIG. 4 by screws 15. As will be seen from FIG. 3 and PEG. 4 the position of plunger means 14 is shown as being located beneaththe center of each segment tending to urge each segment away from the hub 19 of mandrel 1.

The details of spring plunger means 14 are illustrated in FIG. 6. Referring to FIGS. 4 and 6, it will be seen that plunger'lS with contacting surface 1% is activated by spring 17 which continually urges plunger 18 radially outwardly from huh 1t} and, as positioned in FIG. 4, it will be apparent that said plunger means continually urges segment 3a radially outwardly from hub 16. Spring plunger means 14 have adjusting screws 16, for adjusting the stroke of plunger 13 over the range indicated by a in FIG. 6, the plunger being retained within the housing of the plunger means by appropriate collars as shown.

As illustrated in FIGS. 3 and 4, segment 3a is compressed tightly as far as it will go, with its concave face butting against the circular edge of front and rear vicinity of the center of said segments. Obviously, inherent in such structure, and readily recognized by one skilled in the mechanical arts, particularly in view of the function of said segments in the apparatuses described herein, is the fact that said cross-section acts as a simple, solid-truss beam, during rotation of the mandrel, with the resultant of the centrifugal forces exerted radially outwardly, being concentrated at the central, thickest portion of said cross-section, flanges 22 and 23 respectively, at each end of said cross-section, completing the simple beam concept illustrated by exerting the necessary forces at each end of said cross-section, during rotation, to counteract said centrifugal forces. As is also readily apparent from FlG. 4, discs 2 and 2' are in radial tension during rotation due to centrifugal force and, as they constitute the primarysupporting structure for said segments during the rotation, it is equally apparent that their minimum thickness must be a function of the load (segments) they must carry during rotation. The lighter in weight said segments are, obviously the thinner and lighter in weight said discs may be constructed. Said se ments are lighter than previous segments, as illustrated, by virtue of their cross- 'section designed in the form of a simple, solid-truss beam-like cross-section, which novel cross-section forms the crux of our invention.

Thus, in operation, a cylindrical 'distensible tube 20, shown only in cross section in FIG. 4, preferably of cardboard, having an interior dimension c as shown in FIG. 4, is fitted onto the mandrel over front circular member 2 and forced over the segments 3a, 3b, and 3c, aided by the angular slope of the front edge of said segments, corresponding approximately to the angle alpha, indicated in FIG. 5. As the distensible tube 20 is slid over the mandrel, it ultimately comes in contact with flange 21 of rear circular member 2',-said tube having the effect of compressing all three segments to their innermost position, as shown in FIG. 4.

The internal stress exerted against the interior of the tube Ztl, by virtue of the segments 3a, 3b, and 3c being urged to their outermost position by plunger means 14, holds the tube Ell firmly in place. while the mandrel is at est. As the mandrel is rotated at high speeds, plunger means 14 combined with centrifugal force, cause segments 3a, 3b, and 3c to exert increased pressure against the interior of tube 2% and as strand is wound thereon, such internal, outward stress tends to counteract the compressive forces built up by such strand.

' Rotatable hub 10 is suitably threaded, 24, to receive a shaft, driven by motor means not shown, for rotating mandrel 1.

When the winding tube 20 has been filled with strand, the mandrel is brought to rest, centrifugal forces diminish to zero and the filled tube may be readily removed from the mandrel against the slight friction between the tube and segments 3a, 3b, and 3c resulting from the constant moderate pressure against said segments exerted by plunger means 14. Once the windin tube is completely removed from the mandrel, segments 3a, 3]),2111d 30 move to their outermost position under the influence of plunger means 14 through the distance indicated by b in FIG. 4 until the retaining flange 22, best illustrated in FIG. 5, engages corresponding flanges 23 on the interior faces of end discs 2 and 2, which flange 23 is in the form of an annular ridge concentrically positioned on the interior face of each disc 2. Flanges 22 and 23 may be replaced, if so desired, with radially and intermittently spaced lugs or steps to perform the same function.

As is quite apparent from the foregoing, depending upon the type of fibrous material being wound upon our novel mandrel, the winding tube may be completely eliminated and the fibrous material wound directly onto our mandrel. This is possible because our mandrel presents substantially a continuously cylindrical working surface for winding, without the need for the intermediate winding tube between mandrel and wound strand. When direct winding is desired, and strand is wound directly upon the mandrel, the compressible working surface of our novel mandrel permits ready withdrawal therefrom of the wound strand package after the mandrel is brought to rest. I

Furthermore, although our preferred embodiment employs spring plunger means 14, they may be eliminated entirely without detracting from the utility of our inven tion, since centrifugal force provides the primary means for counteracting compressive stresses of fiber Wound at high speeds.

We claim:

1. In a rotatable mandrel adapted to have wound thereon at hi h speeds continuous fibers, said mandrel comprising a rotatable hub, a multiplicity of substantially identical segments of a hollow cylinder, said segments positioned generally symmetrically and radially equidistant from said hub, a first connecting means co-acting between said hub and said segments for maintaining said segments radially in variable spaced relationship with respect to the axis of rotation of said hub, said first means comprising a pair of generally circular members having two faces respectively, each said member positioned generally parallel with respect to the other, and fixed to said hub and rotatable therewith, said circular members each having an annular flange in the interior face thereof and generally concentric with respect to the axis of rotation of said circular members, said annular fiange positioned adjacent the periphery of said circular member, said cylindrical segments positioned generally symmetrically and radially equidistant from said hub, each of said segments having a generally convex and concave face and an axis of rotation generally coincident with the axis of rotation of said hub, said segments having annular flanges fixed to their concave face and generally adjacent and parallel to a curved edge of said cylindrical segment, said annular flanges of said cylindrical segments corresponding with and engaging said annular flanges of said circular members, a second means for urging said cylindrical segments away from the axis of rotation of said hub to the limit permitted by the engagement of the aforementioned flanges, said second means permitting said cylindrical segments to be compressed and moved radially toward the axis of rotation of said hub, said compressive movement of said cylindrical segments limited by contact between said cylindrical segments with said circular members, the improvement, in combination therewith, of each of said segments, when viewed in cross-section as an individual segment, independently of the remainder of said multiplicity of segments, having said cross-section taken in a plane passing through the axis of rotation of said mandrel, said cross-section displaying substantially a straight line corresponding to the convex working surface of said segment, said straight line being substantially parallel to the axis of rotation of said mandrel, said cross-section of said individual segment becoming progressively thinner, respectively, toward each of its extremities from its center, as manifested by a line corresponding to the concave surface of said segment, said latter line being farthest from said straight line corresponding to the convex working surface of said segment, at the center portion of said cross-section, said latter line assumingan attitude of convergence with respect to said straight line, respectively, progressively toward each extremity of said individual segment, from the center of said segment.

2. The mandrel of claim 1 wherein said second means for urging said segment away from said hub and for ermitting said segment to be compressed, are springs.

3. The mandrel of claim 1 having at least three cylindrical segments.

4. The mandrel of claim 1 wherein each said cylindrical segment subtends an angle greater than 20 degrees.

References Cited by the Examiner UNITED STATES PATENTS 2,274,681 3/42 Fletcher 242-18 2,457,786 12/48 Slayter 242-18 2,576,254 11/51 Fletcher 242-82 X FOREIGN PATENTS 891,964 12/43 France.

MERVIN STEIN, Primary Examiner.

RUSSELL C. MADER, Examiner. 

1. IN A ROTATABLE MANDREL ADAPTED TO HAVE WOUND THEREON AT HIGH SPEEDS CONTINUOUS FIBERS, SAID MANDREL COMPRISING A ROTATABLE HUB, A MULTIPLICITY OF SUBSTANTIALLY IDENTICAL SEGMENTS OF A HOLLOW CYLINDER, SAID SEGMENTS POSITIONED GENERALLY SYMMETRICALLY AND RADIALLY EQUIDISTANT FROM SAID HUB, A FIRST CONNECTING MEANS CO-ACTING BETWEEN SAID HUB AND SAID SEGMENTS FOR MAINTAINING SAID SEGMENTS RADIALLY IN VARIABLE SPACED RELATIONSHIP WITH RESPECT TO THE AXIS OF ROTATION OF SAID HUB, SAID FIRST MEANS COMPRISING A PAIR OF GENERALLY CIRCULAR MEMBERS HAVING TWO FACES RESPECTIVELY, EACH SAID MEMBER POSITIONED GENERALLY PARALLEL WITH RESPECT TO THE OTHER, AND FIXED TO SAID HUB AND ROTATABLE THEREWITH, SAID CIRCULAR MEMBERS EACH HAVING AN ANNULAR FLANGE IN THE INTERIOR FACE THEREOF AND GENERALLY CONCENTRIC WITH RESPECT TO THE AXIS OF ROTATION OF SAID CIRCULAR MEMBERS, SAID ANNULAR FLANGE POSITIONED ADJACENT THE PERIPHERY OF SAID CIRCULAR MEMBER, SAID CYLINDRICAL SEGMENTS POSITIONED GENERALLY SYMMETRICALLY AND RADIALLY EQUIDISTANT FROM SAID HUB, EACH OF SAID SEGMENTS HAVING A GENERALLY CONVEX AND CONCAVE FACE AND AN AXIS OF ROTATION GENERALLY COINCIDENT WITH THE AXIS OF ROTATION OF SAID HUB, SAID SEGMENTS HAVING ANNULAR FLANGES FIXED TO THEIR CONCAVE FACE AND GENERALLY ADJACENT AND PARALLEL TO A CURVED EDGE OF SAID CYLINDRICAL SEGMENT, SAID ANNULAR FLANGES OF SAID CYLINDRICAL SEGMENTS CORRESPONDING WITH AND ENGAGING SAID ANNULAR FLANGES OF SAID CIRCULAR MEMBERS, A SECOND MEANS FOR URGING SAID CYLINDRICAL SEGMENTS AWAY FROM THE AXIS OF ROTATION OF SAID HUB TO THE LIMIT PERMITTED BY THE ENGAGEMENT OF THE AFOREMENTIONED FLANGES, SAID SECOND MEANS PERMITTING SAID CYLINDRICAL SEGMENTS TO BE COMPRESSED AND MOVED RADIALLY TOWARD THE AXIS OF ROTATION OF SAID HUB, SAID COMPRESSIVE MOVEMENT OF SAID CYLINDRICAL SEGMENTS LIMITED BY CONTACT BETWEEN SAID CYLINDRICAL SEGMENTS LIMITED BY CONTACT BERS, THE IMPROVEMENT, IN COMBINATION THEREWITH, OF EACH OF SAID SEGMENTS, WHEN VIEWED IN CROSS-SECTION AS AN INDIVIDUAL SEGMENT, INDEPENDENTLY OF THE REMAINDER OF SAID MULTIPLICITY OF SEGMENTS, HAVING SAID CROSS-SECTION TAKEN IN A PLANE PASSING THROUGH THE AXIS OF ROTATION OF SAID MANDREL, SAID CROSS-SECTION DISPLAYING SUBSTANTIALLY A STRAIGHT LINE CORRESPONDING TO THE CONVEX WORKING SURFACE OF SAID SEGMENT, SAID STRAIGHT LINE BEING SUBSTANTIALLY PARALLEL TO THE AXIS OF ROTATION OF SAID MANDREL, SAID CROSS-SECTION OF SAID INDIVIDUAL SEGMENT BECOMING PROGRESSIVELY THINNER, RESPECTIVELY, TOWARD EACH OF ITS EXTREMITIES FROM ITS CENTER, AS MANIFESTED BY A LINE CORRESPONDING TO THE CONCAVE SURFACE OF SAID SEGMENT, SAID LATTER LINE BEING FARTHEST FROM SAID STRAIGHT LINE CORRESPONDING TO THE CONVEX WORKING SURFACE OF SAID SEGMENT, AT THE CENTER PORTION OF SAID CROSS-SECTION, SAID LATTER LINE ASSUMING AN ATTITUDE OF CONVERGENCE WITH RESPECT TO SAID STRAIGHT LINE, RESPECTIVELY, PROGRESSIVELY TOWARD EACH EXTREMITY OF SAID INDIVIDUAL SEGMENT, FROM THE CENTER OF SAID SEGMENT. 